1. Field of the Invention
This invention relates generally to the field of vehicles and more specifically to the control of vehicles equipped with hinged bodies and body covers.
2. Description of the Prior Art
The incorporation of a hinged body with a vehicle chassis is well known in the prior art and dates back at least to the first railroad freight carrying cars and to the ore carrying cars in the mining industry.
The motor vehicle industry is a relative new comer to hinged bodies but the truck divisions of motor vehicle manufactures have found reasons to include hinges on all sides of cargo bodies and cabs. Most of the interest in the hinged body centers around the hinge itself, size and placement, and the means for tilting the body relative to the chassis, power, manual and manual assist.
Since most bodies are rotated or tilted when the vehicle is at rest, research centers around the static forces involved in that mode. Little consideration is given to the dynamic forces that come into play when the vehicle is moved at a substantial speed while the body is tilted away from normal.
By way of example, U.S. Pat. No. 4,629,243 issued Dec. 16, 1986 to Jensen discloses a hinge system for open bed vehicles and allows that the cover may be tilted from either side and even supplies a rod 35 to support the cover in the tilted position, however nothing prevents the cover from lifting off the rod in the event of the application of dynamic wind forces.
Similarly U.S. Pat. No. 4,819,981 issued Apr. 11, 1989 to Moe et al. show a bed cover mounted in a hinged relation with the vehicle body and biased arms 64 and 70 for supporting the cover in the tilted position. Moe et al concede that the cover is not stable unless the cover is down and locked. U.S. Pat. No. 4,943,108 issued Jul. 24, 1990 to Turnbull discloses a hinged cover in two sections restrained by chains in the tilted position. U.S. Pat. No. 5,131,712 issued Jul. 21, 1992 to Heinz relates to a frame attached to a bed cover that is hinged on one side and utilizes a power unit 58 to raise and lower the cover and further supplies a flexible connector 94 to prevent over rotation of the cover about its hinge.
It can be clearly seen then, that there is a continuing need for a simple yet secure means for controlling the tilt of vehicle bed covers under both static and dynamic conditions.